The Hemophilia Growth and Development Study (HGDS) is a study which is examining the natural history of HIV infection in HIV-infected hemophiliac children since 1988. Data is gathered on the study participants from 14 U.S. medical centers, which shall be under subcontract to the referenced Contractor. Data collection is anticipated to continue through 12/31/95. Given the unique characteristics of the study cohort that has been established, it has been determined that it is desirable to maintain portions of the cohort to meet the following research aims, both ongoing and new: a) To further elucidate the effects of HIV on physical growth and development by studying stature, growth velocity and sexual maturation. b) To determine whether disturbances in physical growth (decreased stature, growth velocity, delays in sexual maturation) predict HIV disease progression. c) To provide a better understanding of HIV pathogenesis in hemophiliacs through performance of detailed virologic and molecular analysis. d) To evaluate the recognition phase of immune response, as analyzed by in vitro lymphocyte responsiveness, to define cell mediated immunity relationships that are characteristic of long term survival in hemophiliacs with HIV disease. e) To follow neurological and neurological changes in the study cohort to a limited extent based on the results observed to date. This contract will support a data and study coordinating center, which will continue the data collection specified in the original study protocol and which will supply the necessary support services for data collection, editing, management, analysis, and reporting.